Gaseous electric discharge device



Oct. 6, 1936. M. PlRANl ET AL 2,055,907

" -GASEOUS ELECTRIC DISCHARGE DEVICE Filed Feb. 10, 1932 ATTORNEY Patented Oct. 6, 1936 ,GASEOUS ELECTRIC DISCHARGE DEVICE Marcello lirani, Berlin-iwilmersdorf, and Karl Becker, Berlin-Steglitz, Germany, assignors to General Electric Com New York Application February 10, 1932, Serial No. 592,138 any February 27,1931

In Germ pany. a corporation or 4Claims. (01. 176-122) The present invention relates to gaseous electric discharge device'sgenerally and more particularly the invention relates to such devices in which the gaseous electric discharge is of the concentrated or so-called stringy type. This type of discharge is produced when the gas or vapor pressure and the current are higher than those used when "a diffuse discharge is desired in an electric discharge device; Such a dischargepossesses two advantages, first, it is more eflicient giving a more intense light emission, and second, since the discharge occupies onlya small portion oithe cross section of the tube, a. glass having a lower melting point and being more easily workable may be used than if the same current were used in an identical device without a "stringy" discharge. This latter advantage hasv not been obtained in previous devices of-this type since the stringy gaseous electric discharge colzg umn constantly changed its position in the container and often closelyapproached the container walls to their great injury.

- The object of the present invention is to provide 'an electric discharge device having a g5; stringy electric arc dischargedn which the con tainer is made of a softer glass than has hitherto been found practical in similar devices having a "stringy electric arc discharge. Still further objects and advantages attaching to the device and so to its use and operation will be apparent to them skilled in the. art from. the following particular description.

The invention attains its object by providing along the positive column discharge path between the electrodes of a gaseous electric discharge deyice one or more septums perpendicular to the longitudinal axis of the container of. said device, said septum having a diameter which closely approaches the inner diameter of said container and has an opening therein concentric-with the longitudinal axis of said container. Said septum.

0r septums guide the stringy electric discharge in said container to prevent said discharge from approaching too closely the soft glass walls of said container and thus serve to protect said walls from injury thereby. The septum is supported in the container byany of the methods well known a in the art. Said septum is madeoi a material having a higher melting point than the walls of said container and may be of quartz or of a high melting point metal such as molybdenum, or I tungsten. If. the septum is of metalit should be thoroughly degassed before thedevice is placed into operation.

' Each of the discharge supporting electrodes of the device in, the preferred embodimentis sur-. rounded by a cylinder made of like materials as said septum and partially closed in the direction of the discharge path to guide the discharge. in .the region of the electrodes and thus to protect 5 the soft glass walls of the container in that region.

In the drawing accompanying and forming part of this specification two embodiments of the new and novel gaseous-electric arc discharge 10 device are shown, in side elevation.

I Fig. 1 is a side elevational, partly sectional view of one embodiment of the invention, and

Fig. 2 is a similar view of another embodiment of the invention. 1

Like numbers denote like parts in both figures. Referringto Fig. 1 of the drawing the new and novel gaseous electric discharge device comprises a container I having a thermionic electrode 2 at each end thereof. Electrode leads 3 of said electrodes 2 are sealed into the pinch parts 4 of stems 5 of said container I. Said electrodes 2 are of the sintered, mixed metal and oxide type made in accordance with the disclosure of co-pending application, Serial Number 377,044, filed July 9, 1929 being the invention of Marcello Pirani and Hans Ewest, or when desired any other suitable type of thermionic electrode maybe used. Said electrodes Z'are brought to an electron emitting temperature by an initial glow discharge which rapidly turns into thedesir-ed arc discharge, or when desired by a heating filament adapted for that purpose. A septum t which, when desired, is of ,metal such as molybdenum is provided in said container i equidistant from the ends .of said container l and is perpendicular to the-longitudinal axis of said container 5. Said septum t is supported in said container l by flange 8 thereof pressing against the inner wall of said container 6 and the diameter of said septum 6 is co-extensive with the inner diameter of said container E. An annular opening I is provided in -said septum 6, and said opening 1 is concentric with the longitudinal axis of the container 6. Each of said electrodes 2 is surrounded by a metal cylinder 9 which is concentric therewith and which has in the direction of the discharge path a flange ill with an opening ll therein, and said opening it is concentric with the longitudinal axisof the container I. Said shells 9 are supported by supports ll' sealed in pinch-partst oi. stems 5,

Said container i isgreater in diameter in the middle thereof than atits ends to maintain septum 8 in desired positionland is filled with. an

electric discharge conducting gaseous atmosphere at apressure higher than normal to said device a body 52 of vaporizable metal such as mercury in the order of 1 cm. is placed in said con.-

tainer I. In such a device a current of 34 amperes with a potential of--29 volts and 1000 watts applied to the electrodes 2 of the device produces a concentrated, stringy electric discharge between said electrodes which is guided by openings i and ii and prevented from changing its position sufficiently-from the normal discharge path between said electrodes 2 to injuriously affeet the walls of said container, so that a softer glass may be used in the walls of said container ll than in a similar device in which the stringy electric discharge is not guided.

When desired, the cylinder 9 surrounding said electrode 2 is connected by a lead I l having therein resistance I3, to the lead 3 of that electrode 2 to which it is adjacent, as illustrated in dotted lines on the left side of the drawing. This construction creates an electric field about each of the electrodes 2 to decrease the rate of disintegration thereof, and, further, when desired, said cylinder 9 is connected by lead l6, containing a high resistance I5, to the lead 3 of the electrode 2 opposite that electrode 2 to which it is adjacent, as illustrated in dotted lines in the right side of the drawing, said cylinders 9 then serve as auxiliary electrodes during the starting of the device.

It will be understood fromthe above descrip tion that the invention lends itself to a curved type of container in addition to the substantially straight type shown-and described in Fig. 1. For example, in the -U shaped tube shown in Fig. 2 the electrodes 2 in the container I are in the same plane and close to each other and the container l is in the shape of two substantially parallel tubes'perpendicular to the plane of said electrodes 2 with a curved tube portion connecting said parallel tubes, perforated septums S, 6',

6" are arranged at the bends. or curves in said container 5 along the discharge path in such manner that the stringy electric discharge are path extending from the electrodes 2 to the opening 1 or 1'. in the septum 6 or 6", and from the opening I or 'I in septum 6 or 6" to the opening in septum 8' is not invaded by the walls to the plane of said electrodes and a curved porare discharge than would be practical if the stringy electric discharge were not guided and. controlled by the means set forth in this invention.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by 10 those skilled in the art without departing from the broad spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An electric arc discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein under a pressure high enough to support an arc discharge, and a perforated septum separated ,from said electrodes and mounted along the part of the discharge path between said electrodes occupied by the positive column'of an arcdischarge, said septum being transverse to the discharge path in said. container and guiding an electrical constricted arc discharge in said container away from the walls thereof'to prevent destructive action thereby on the main wall of said container.

2. An electric discharge device comprising a container, electrodes sealed therein,--a gaseous.

atmosphere therein, said electrodes being surcylinders being adapted to guide the electric discharge in said container away from the walls thereof. i

3. An electric discharge device comprising a curved container, electrodes sealed therein, a gaseous atmosphere therein, and a perforated septum along the discharge path between 'said electrodes, said septum beingtransverse to the discharge path and located at the bends in said container between said electrodes and adapted to guide the electric discharge in said container away from the walls thereof.

4. An electric discharge device comprising a curved container, electrodes sealed therein, a

gaseous atmospheretherein, and a plurality of. perforated septums in said container, said electrodes being in the same plane, said container comprising two parallel portions perpendicular tion connecting said parallel portions, said perforated septums being arranged along and transverse'to the dischargepath and at the bends in said container so that the path of the electric discharge extending from electrodes to the opening in the septum and fromthe opening in one septum to the opening in another septum is not invaded by the walls of said container.

MARcELLo PIRANI. mar. BECKER. 

